1. Field of the Invention
The present general inventive concept relates to an image forming apparatus, and in particular, to a developing device used with an electrophotographic image forming apparatus, which comprises an image carrier and a developer carrier to print an image onto a print medium, and further comprises a developer scattering prevention unit to prevent a developer from scattering between the image carrier and the developer carrier.
2. Description of the Related Art
Image forming apparatuses, such as printers, copying machines, facsimiles and multifunction peripherals, are typically used for printing an image onto a print medium and classified into ink-jet image forming apparatuses and electrophotographic image forming apparatuses depending on printing types thereof.
FIG. 1 shows a conventional electrophotographic image forming apparatus (laser beam printer) 100.
Referring to FIG. 1, the electrophotographic image forming apparatus 100 comprises a paper-feeding device 110, a developing device 120 and a plurality of rollers 101 to 103 for transferring print mediums from the paper-feeding device 110.
The developing device 120 comprises an image carrier 121 for printing an image on a print medium, a laser scan unit 129 for causing an electrostatic latent image to be formed on the image carrier 121, a cartridge 125 for receiving developer T in a housing 128 thereof, a developer carrier 122 for feeding the developer in such a way that an image is formed according to the electrostatic latent image, and an image transfer member 124. The image carrier 121 and the developer carrier 122 are formed in a roller shape as shown in FIG. 1 or in a belt shape depending on a type of the image forming apparatus 100.
In the developing device 120 constructed as described above, air flows between the image carrier 121 and the developer carrier 122 along a rotating direction of the image carrier 121 (along a running (moving) direction of the image carrier 121 if the image carrier 121 is formed in the belt shape) as the image carrier 121 rotates (see arrow A in FIG. 2). Due to this, the developer may scatter through a space between the image carrier 121 and the developer carrier 122, and accordingly, there is a problem in that the developer leaks out of the developing device 120. In order to solve this problem, modern developing devices are further provided with a developer scattering prevention unit.
FIG. 2 shows a developing device for an image forming apparatus provided with a conventional developer scattering prevention unit 130.
Referring to FIG. 2, the conventional developer scattering prevention unit 130 comprises a pair of vacuum sources 131 driven separately from an image carrier 121 and a developer carrier 122, and a pair of duct members 133 located adjacent to an intermediate area between the image carrier 121 and the developer carrier 122. For reference, a reference numeral 135 indicates a filter member for filtering a suctioned developer.
A developing device provided with a developer scattering prevention unit 130 is disclosed in Japanese Patent Publication No.: Hei 11-327295.
Meanwhile, the developing device 120 provided with such a conventional developer scattering prevention unit 130 as described above has to separately include a motor (not shown), a power source connection means for connecting a power source to the motor, and a control device 140 for controlling the motor, because each of the pair of vacuum sources 130 has to be driven separately from the image carrier 121 and the developer carrier 122. Accordingly, there are problems in that a process for manufacturing such a developing device becomes complicated because the construction of the developing device 120 is complicated, and in that manufacturing costs of such a developing device are increased because constituent elements are added.